the rest of unsurpassed master vol6 is 8/73 wake of the flood outtakes and is not included here since it is of much inferior quality to what is on etree
the rest of the rehearsals in this set from bootleg label "Dead Man" is on "unsurpassed master vol5" which is already on etree
Source and date for the bootlegs is not specified and are described as "1971 studio outtakes - 1st sessions with keith godchaux on keyboards"
Deadlists and the Tapers Compendium Vol1 disagree on the order of songs for some of the dates. Deadbase 9 also does not match the others. So it seems the rehearsals have circulated in a number of different versions not on etree.
Quality varies for different songs on the bootlegs and cousinit's versions at etree. The cousinit's versions seem to have the standard cousinit noise reduction processing and added humm on the left channel applied. For example on ripple, the cousinit version sounds slow and is more muffled with more hiss than the "unsurpassed master vol6" version. There are probably other differences between the quality on other songs.The unsurpassed master vol5 has a lot of static in the last track t16. Tapers Compendium Vol1 rates the sound quality B+ for the first 3 dates and A/B for the last date.
I didn't really want to circulate bootleg sources since someone probably has better and can hopefully top the bootlegs, but since no one has come up with anything better in the year since I posted a query about this at the workingmans tracker forum, here it is.